Abstract
This essay contends that Spinoza’s argument for the conatus doctrine does not commit any of the five fallacies of equivocation. The key to a better understanding of his argument lies in a Spinoza’s “theory of inherence” — that is, his theory of what it is to be “in” something. Spinoza’s conatus argument is a valid demonstration from Spinozistic premises about inherence, conception, causation, and related matters. These premises reflect his deep commitment to a rigorous Principle of Sufficient Reason, to a conception of things as causing their own properties through their essences, and to a closely-related conception of causation as identical with or parallel to logical consequence.